In this paper I focus on the discussion between Rawls and Habermas on procedural justice. I use Rawls’s distinction between pure, perfect, and imperfect procedural justice to distinguish three possible readings of discourse ethics. Then I argue, against Habermas’s own recent claims, that only an interpretation of discourse ethics as imperfect procedural justice can make compatible its professed cognitivism with its proceduralism. Thus discourse ethics cannot be understood as a purely procedural account of the notion of justice. Finally I draw the different consequences that follow from this reading